1. Field of the Invention
The present invention generally relates to devices for interconnecting telecommunications lines, and more particularly to a modular connector for a plurality of optical fibers.
2. Description of the Prior Art
In the last few years, optical fibers have replaced copper wire as the preferred medium for carrying telecommunications signals. As with copper wire, it is necessary to provide for the interconnection of optical fibers, during installation, repair or replacement of the fibers. There are generally two kinds of interconnection devices, splices and connectors. The term "splice" usually refers to a device which provides a permanent connection between a pair of optical fibers. Many fiber optic splices employ plate elements having fiber-receiving V-shaped grooves, with means for clamping the terminal ends of a pair of fibers in a common groove. Some of these devices are designed to interconnect a plurality of pairs of fibers. See, e.g., U.S. Pat. No. 5,151,964. The term "connector," in contrast, usually refers to a device which may be engaged and disengaged repeatedly, often with a different plug or receptacle. The present invention is directed to such a device, although the term "connector" should not be construed in a limiting sense since the present invention may inherently provide a permanent, as well as temporary connection.
There are two primary types of commercially available fiber optic connectors, namely, ferrule connectors and biconic connectors. Ferrule connectors use a ferrule plug, typically ceramic, having a central bore which receives a single optical fiber. Biconic connectors use a plug in the shape of a truncated cone. Both connectors usually combine a pair of plugs fitting into a common socket or receptacle to provide a completed connection. The prior art also includes hybrid ferrule connector/splices, such as those shown in U.S. Pat. Nos. 4,986,626 and 5,159,655.
One area which has not been adequately addressed by the prior art, however, is the interconnection of a plurality of fiber optic pairs in a manner which provides for quick disconnection and reconnection. Since the plugs of ferrule and biconic connectors receive only a single fiber, a relatively large bank of such connectors must be provided to interconnect several fiber pairs. Alternatively, two or more plugs may be ganged together, e.g., in a duplex connector, as shown in U.S. Pat. No. 5,101,463. One drawback with these multifiber connectors is the poor interconnection densities that are achieved. While some ferrule designs have densities around 2 connections per square centimeter, this may be compared to densities of 4 connections or more per square centimeter in some copper connectors, such as an RJ45 connector. Some non-ferrule designs provide slightly improved densities, such as that described in U.S. Pat. No. 4,045,121, but that connector has far too many parts and is not easily installed. The '121 connector may also be contrasted with the RJ45 copper connector which possesses the desired characteristics of ease of installation, simplicity of use and quick disconnection.
Another problem in multifiber connectors is alignment of the interconnected fiber pair. For example, in the connector depicted in European Patent Application No. 514,722 (commonly referred to as an "MT" connector), pins are used to align the connector parts, but it is still difficult (i.e., expensive) to provide the strict tolerances required for high performance optical connections. Consequently, this connector exhibits relatively low performance. Other techniques have been used to improve alignment, such as the V-grooves shown in the '964 splice, but unfortunately, these techniques have not been suitably adapted for use in a disengageable connector. Furthermore, the MT connector is designed for pretermination of the fibers at the factory, i.e., it is very tedious to field install. It would, therefore, be desirable to devise a fiber optic connector which provides for the quick disconnection and reconnection of a plurality of optical fiber pairs, and which is simple to install and use. It would also be advantageous for the connector to have a reduced part count, exhibit an improved interconnection density, and provide precise alignment for enhanced performance.